Aegolius13

If you just want to get your kerbal down, you can send up an empty ship controlled by a probe core, get it close, and have your kerbal EVA over to the new ship. You don't have to dock, or even match speed exactly. The kerbal jetpack is potent! Just make sure the new ship is not crewed (kerbals like to sneak in), and the hatch is not obstructed. If you actually want to land the old ship, your main options are to transfer fuel, or to connect it to a de-orbiter craft that will reenter with it. In either case, docking is required. But once you get the claw, you can use that even if the current ship does not have a docking port.

If you have it, it may also help to use the SAS hold prograde function. It's not a substitute for a stable rocket, but can help correct tipping tendencies before they start compounding. You can still make small adjustments to your ascent path by manual steering, but as a rule of thumb it's best to keep your directional marker within the circle around the prograde marker. Any more than that, and the drag tends to push the rocket further off course in a vicious cycle. That said, it's safer to adjust your course with throttle control and gravity while remaining prograde (throttle down to tip more, and vice versa).

I've noticed something similar when trying to land or aerobrake with less than ideal craft. If I can hold retrograde, the bottom of the stack (e.g. engines and fuel tank) get hot but hang in there. But if the thing tips over, everything blows up almost instantly. Not just the fragile science instruments and solar panels, but even the Mk 1 capsule, which is supposed to have good heat tolerance. No clue why. I would expect the ship to heat up more after doing more of a pancake, but not that much quicker.

I just got my first probe into Moho orbit after two... let's just call them flybys (one mission I was actually able to salvage by redirecting to Eve). I would echo the suggestion of bringing way way more delta-v than the launch planner says you're going to need. With the huge velocities involved, even a small deviation from the ideal launch can lead to much larger capture burns. On that topic, if you're not going automatic with MechJeb or whatnot, fine-tune the crap out of your maneuvers to make sure your transfer orbit is as close to tangent to Moho's orbit as humanly possible. Once I get an encounter, I like to check this by putting a maneuver node at Moho periapsis and seeing how much retrograde delta-v it takes to get a stable orbit. Of course, you will probably need to fine-tune after each burn along the way. It helps to have a decent TWR on the capture burn, since you'll and you'll be flying by very fast and will have a short time to lay down the necessary braking burn. I'm sure people had done it with an ion thruster, but sounds like a very tricky proposition. Which is too bad - Moho could otherwise be great ion probe territory due to the massive delta-v requirements and ample solar energy. Finally, I know some folks have come up with plane change tricks to avoid a huge plane change burn in solar orbit. I haven't really figured this out yet, but it's discussed here: http://forum.kerbalspaceprogram.com/index.php?/topic/134892-whats-the-best-way-to-get-to-moho/

Thanks for the link, very interesting stuff that I was not aware is coming. But not quite sure I understand -- are they saying the RGUs are just going to be relays from now on, or are also going to retain their probe core functionality? If they're just relays, I would be sad to lose the little RGU, since as mentioned above I use it all the time (and am surprised the Squad folks are saying it's underused). It's small, not that heavy, not that expensive, easy to fit in almost any design, and definitely more subdued aesthetics-wise than the OKTO-2.

I think there needs to be some redesign on the RC-L01, which is the 2.5m probe, a/k/a Remote Guidance Unit. I must say I love its little brother, the RC-001S - the latter is my go-to probe core for most ships (both manned and unmanned) due to full SAS functionality. Unfortunately, the bigger RGU is inferior in almost every way. It's much heavier (0.5 tons vs 0.1), uses more electricity, and has only tiny improvements in SAS torque and electricity storage. Apart from looking bad next to its little brother, the RC-L01 is also completely eclipsed by both the new HECS-2, and even the Mk2 drone core. Both feature substantially more battery storage and torque, for much lower mass. The Mk2 is even pretty competitive in cost. The HECS-2 costs more, but I guess you pay for the ease of not needing separate batteries and reaction wheels, as well as the "cool factor." And truth be told, I don't care much about spending a small amount more on my spiffy resuable ships or interplanetary craft. Thus, it seems the only real reason you'd ever currently use the RC-L01 is if you have a 2.5m stack and absolutely no place to put a 1.25m probe core. But that's seldom the case - even on bigger ships I almost always have a tapered front end, with a medium docking port or the like in front, where a probe core could fit. Heck, if you had no other options you could put in a 2.5m service bay, put NOTHING in it but the smaller RGU, and STILL come out ahead mass-wise. It seems like there are two decent solutions. The first, more humdrum one, is to just reduce the mass and power consumption to be more in line with the smaller RGU. Basically, imagine the Kerbal engineers took the little one, and did nothing more with it than encased it in an adapter to fit the 2.5m form factor. Since we have some pretty darn light 2.5m parts (Rockmax adapters, Z4k battery, big reaction wheel), it's apparent "in world" that just building a thin disk to the 2.5m form factor should not add a ton of weight. The second option, which I'd endorse, is to leave the RC-L01 somewhat heavy, and maybe increase the cost, but add some better features to balance it out. More electricity storage and torque would be goods starts, again to make this competitive with the OKTO-2 as a one-stop solution for several needs. But there are probably more interesting options as well. Maybe a little monopropellant, like with the manned command modules? It's a pain to have to lug even the tiny-sized monopropellant tank if you want to dock an unmanned craft. Built-in static solar panels or RCS thrusters? Something brand-new? At the end of the day I don't really care if it's not the more practical part ever, but it should at least be interesting and not all-around worse than previous parts. It's an end-line part that takes 1,000 science to get. That alone should demand a cool factor, and right now it's just not there.

That's my tentative plan going forward... stick the Klaw at the end of a couple orange tanks, a long string of Mk 1 liquid fuel fuselages, and/or some girders. Hopefully the extra rear clearance will allow me reduce ore eliminate the engine angle from the original, which should provide extra thrust to make up for the additional tail weight. And of course, even if a little of the thrust is blocked by the asteroid, fuel should still be plentiful as I'll be mining the asteroid while pulling it. So all I really care about is being able to pull relatively straight.

I thought of that, but I did compare my original and revised versions with the same test launchpad set-up, so the only variable was the engine angle. They were both pretty slow, but the version with the more-angled engines was much slower -- could barely out-thrust even the hacked gravity. The second version was like one angle-snap click away from perpendicular, so given the cosine function for engine loss, I'm now not surprised I got next to no thrust.

Ah, think it's starting to make sense. I think the part I was missing when the engines are highly inclined, the engines are spending most of their effort just pushing two streams of exhaust in mostly-opposite directions... which of course would not do a lot to move the ship. Like how a boat with propellers at both ends would push water out in both directions, but would not move. Back to the drawing board on my asteroid puller, I guess. Thanks much!

Hi all, I've got a bit of an odd question regarding engine thrust. I'm designing an asteroid "puller" to bring in a Class E. I have my nuclear engines out on 4 radially-symmetrical nacelles, which were angled at about 45 degrees to try to clear the asteroid for unimpeded thrust. On my first attempt, the angle was not sufficient, and I had some of the engines (but not all) obstructed by the asteroid, leading to more asteroid-spinning and less asteroid-moving. So to address this, I tried to increase the angle of the engines (i.e., make them closer to perpendicular to the main axis of the ship). I tested out the new design on the launchpad, with gravity hacked and with just the core ship, not the orbital-launch rig. Results were not good- I was barely getting any thrust! In other words, it seems there's a thrust penalty for having your engines angled. I've looked on the forums for info on this and not seen much, but one person suggested the end-thrust is a function of the cosine of the engine angle. My question, I guess, is why. My (probably wrong) understanding was that, if you have two symmetrically balanced engines, as long as there was SOME angle in one direction, they would put full thrust forward regardless of the angle. Those engines' energy has got to go somewhere, and I presume it's not being lost to deformation or heating of the ship in between. If not, the only place the energy could go was forward. The analogy that comes to mind is: squeeze a wet bar of soap between your hands, it will shoot out straight up or in some direction. Not because you pushed it in that specific, but because it's got nowhere else to go when you apply a squeezing force. Can anyone explain what's causing the observed thrust loss? Is there just extra heat generation? Is the specific impulse of the engine affected somehow? Is it just something else? (By the way, if major engine angling is not the answer, I will probably fix my rig by either extending the "tail" so the ship is further in front of the asteroid, or putting the engines out on longer pylons). Thanks for any info you might have!